Keratin-based Nanofibres

Non

Coating of submicrometric keratin fibres on titanium substrates: a successful strategy for stimulating adhesion and alignment of fibroblasts and reducing bacterial contamination.

Coatings are a versatile tool for modulation of the biological response of biomaterials; in particular, the use of biopolymers as coating material may improve cell interactions and tissue adhesion. Among others, keratin is a natural protein able to stimulate fibroblast cells effectively and has the ability to bind metal ions. Coatings of keratin fibers onto titanium substrates can improve soft tissue adhesion, eventually coupling topographical (contact guidance) and chemical stimulus through the alignment of the fibers along sub-micrometric grooves of the substrate. Sub-micrometric keratin fibers were obtained by electrospinning both in random and oriented arrangements (though a rotating collector); in addition, antibacterial properties were added by enrichment of the coating with silver ions. This type of coating can be of interest in transmucosal dental implants, where perimplantitis is often due to infection (biofilm formation) and disease worsening is due to inflammation of the surrounding soft tissue, which is guided by fibroblasts. Keratin fibres coatings were prepared and characterized by means of Field Emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), cell (gingival fibroblasts) and bacteria (S. aureus) culture tests. FESEM observations demonstrated the possibility to deposit keratin fibres onto titanium substrates in random or oriented arrangements effectively. Keratin fibres were able to increase fibroblast adhesion and proliferation. On randomly deposited keratin fibres, fibroblast cells were significantly biologically stimulated and showed high adhesion and proliferation, but not orientation ability; on the other hand, aligned keratin fibres on a grooved substrate were able to stimulate cells both from the topographical (orientation) and biological standpoint. Finally, Ag-doped keratin fibres coatings were able to reduce S. aureus adhesion significantly, maintaining high biocompatibility. Considering these results, keratin sub-micrometric fibres coatings are a promising strategy for stimulating fibroblasts and reducing bacterial contamination

The use of Keratin in biomedical applications

Keratins are naturally derived proteins that can be fabricated into several biomaterials morphologies including films, sponges and hydrogels. As a physical matrix, keratin biomaterials have several advantages of both natural and synthetic materials that are useful in tissue engineering and controlled released applications. Like other naturally derived protein biomaterials, such as collagen, keratin possess amino acid sequences, similar to the ones found on extracellular matrix (ECM), that may interact with integrins showing their ability to support cellular attachment, proliferation and migration. The ability of developing biomaterials that mimic ECM has the potential to control several biological processes and this is the case for keratin which has been used in a variety of biomedical applications due to its biocompatibility and biodegradability. This review describes the progress to date towards the use of keratin in the field of wound healing, tissue engineering and drug delivery applications, with highlight to reports of particular relevance to the development of the underlying biomaterials science in this area

Keratinous Materials as Novel Absorbent Systems for Toxic Pollutants

A range of hazardous organic and inorganic compounds, and metal ions generated by human and industrialactivities leads to serious concerns for environments. Adsorption technologies based on polymeric materials are beingused to remove toxic substances from air and wastewater streams. Keratin protein, found abundantly in sheep’s wool,human hair and bird feathers, is an interesting and potentially useful renewable biopolymer. It contains a variety offunctional groups on the backbone and side chains of the proteins, and is an ideal component to fabricate a rangeof novel adsorbent systems for separation of toxic pollutants via physisorption or chemisorption mechanisms. Inthis review article, the key activities on keratin research and development with respect to the novel properties ofkeratin proteins and their utilization as absorbents or filtration systems are summarized. It is apparent that keratinsin the form of loose fibers, non-woven fabrics, short fibers or particles, membranes and colloids can be used as absorbents for air filtration and wastewater treatment. Keratin materials have potential to be applied in biological and chemical defence applications, and also in protection against radioactive elements.Defence Science Journal, Vol. 64, No. 3, May 2014, pp. 209-221, DOI:http://dx.doi.org/10.14429/dsj.64.731

Preparation and characterization of keratin-K2Ti6O13 whisker composite film

Wool is the most popular natural material. In the textile industries, a lot of waste wool fibres and their products induce actions which lead to the regeneration of wool keratin materials. However, the most significant limitations may be the poor fracture resistance of neat keratin materials. Traditionally, biopolymer was used to enhance the mechanical property of wool keratin material, but it limits the application of the keratin material as a biomaterial. In this article, it was firstly proposed that potassium hexatitanate (K2Ti6O13) whiskers be used to reinforce keratin film. The effects of coupling agent, whisker content, distribution and orientation on properties of composite were investigated by microscope and tensile testing. It was found that K2Ti6O13 whiskers can effectively improve the mechanical properties ofkeratin films

Studies in Green Hydrolysis of Waste Wool

A large amount of raw wool, practically unserviceable for textile uses, is generated in Europe from sheep shearing and butchery; this is a byproduct that is either dumped, burned or sent to landfill. Following the European Commission regulations on animal by-product control, unserviceable raw wool is classified as a category 3 special waste materials, and its collection, storage, transport, treatment, use, and disposal is subject to European Union regulations because of a potential risk source to human and animal health. Raw wool has a noticeable chemical potential to conceive and generate a broad category of products, spreading from protein-based scaffold tissues to fertilizers. Considering all these points, raw wool has potential to create a circular economy rather than just wasted as an unserviceable material. In general, raw wool finds its application in insulation panels, composites, carpets, etc., but needs a complete pre-treatment before use. The problems begin with the use of raw wool is that; it cannot be used as a fertilizer without any previous pretreatment such as washing because of the potential risk of infection and its slow degradation process in the soil environment. For these reasons, fertilization with untreated greasy wool is forbidden by the EU legislation, which strictly provides guidelines for raw wool storage, transportation, and disposal. These costs heavily weigh on the profit of sheep farmers. The primary objective of this study is to develop the cost-effective, sustainable process to use raw wool prior to any pretreatment. This study aims at • Converting waste wool into nitrogen fertilizers at a commercial scale for grassland management and cultivation purposes. • Development of potential novel applications of hydrolyzed wool In order to achieve the desired aim of fertilizer, the chemical breakdown of wool needs to be done using sustainable way, i.e., chemical-free process. In general, hydrolysis process is performed using acids, bases, and enzymes. The literature survey on existing hydrolysis processes, their limitations, industrial scale-up viability, sustainability, cost-effectiveness, etc., lead towards the process where chemical transformation is based on a green economically sustainable hydrolysis treatment using only green solvent superheated water. The other the advantage of green hydrolysis is that it sterilizes the wool at high temperature, which indirectly overcomes the problem of pretreatment prior to use and infection problem in the application phase.In order to understand the extent of degradation and industrial viability of the superheated water hydrolysis process with the aim of fertilizer; the development the process implies two steps: the first one at laboratory scale (batch process) and the second at semi-industrial scale (continuous process). A set of experiments on batch scale reactors was performed to monitor process parameters and extent a degree of hydrolysis on raw wool; to establish the ground for designing and construction of semi-industrial scale reactor. The green hydrolysis process optimization was carried out in batch and semi-industrial scale reactors by varying parameters such as temperature, wool density, material to liquor ratio, time, depending on the extent of degradation of the final hydrolyzed product. Controlled treatment with superheated water converts wool keratin into simpler compounds. At the end of the process, it is possible to obtain a hydrolyzed product in either solid or liquid phase depending on the extent of hydrolysis parameters implemented. The presence of amino acids, primary nutrients, and micronutrients in wool hydrolyzates, along with a concentration of heavy metals below the standard limit, confirm the possibility of using wool hydrolyzates as nitrogen based ecologically sound fertilizer. On the way to find the possible application of keratin hydrolyzate other than fertilizer, which overcomes the environmental problem of wool waste and byproducts were found to be a foaming agent for dyeing. The foam-forming the behavior of the keratin hydrolyzate along with its application in dyeing was studied to develop sustainable and green dyeing process. The surface tension, foam stability, blow ratio, bubble size of the keratin hydrolyzate in aqueous solutions with and without dyeing auxiliaries were determined. The dyeing influential parameter such as wet pickup was studied to identify their effect on dye fixation and color strength. The foam dyeing was compared with conventional cold-pad batch and pad-steam processes for cotton and wool, respectively. The combination of green hydrolysis and the biodegradable keratin hydrolyzate resulted in the sustainable green dyeing process

Studies on Woolen Threads from Historical Tapestries

Fourier transform (FTIR) attenuated total reflectance (ATR)and second derivative spectroscopy has been used for the first time to evaluate the state of degradation in historical woollen threads from the collections of Flemish tapestries (15th-17th centuries) in the Royal Palace, Madrid, Hampton Court Palace, and museums in Brussels. The work was performed as part of the EC-funded project ‘Monitoring of Damage in Historic Tapestries’, also known as the MODHT project. The overall aim was to develop procedures for recognising tapestries at risk and provide analysis for informing collection care. Prior to the testing of the historical threads, model tapestries were prepared according to traditional techniques of weaving and dyeing. They were then subjected to accelerated light ageing. This paper reports on the part of the MODHT project in which ATR-FTIR was used. It was selected since it is a non-destructive method, and also because it has previously been used to study the oxidation products of cystine in wool and to provide a semi-quantitative assessment of change. Evaluation was conducted on the model tapestries, and the cysteic acid peak was selected as the marker for change, as it showed a systematic change with light ageing. The same marker was usedto assess the change in historical threads

Developing keratin sponges with tunable morphologies and controlled antioxidant properties induced by doping with polydopamine (PDA) nanoparticles

his work investigates the preparation of wool keratin sponges by freeze-drying procedure starting form keratin aqueous solutions. The study highlights the correlations between process parameters (protein concentration and freezing rate) and the chemical-physical properties of the final sponges. In particular, as the keratin concentration increases from 1 to 20% wt, the mean pore size and the porosity decrease from 62 to 37 mu m and from 94 to 50% respectively, while the chemical stability in physiological conditions increases, as well as the thermal stability and the elastic modulus. On the other hand, the increase of the freezing rate affects the design of sponges that appear as stacked leaflets structures with oriented pores. Moreover, in order to confer to keratin sponges antioxidant properties, polydopamine (PDA) nanoparticles were used as fillers. To this end, PDA nanoparticles of about 130 nm were successfully dispersed in the sponges, bestowing time-dependent anti-oxidant properties on the scaffolds, with no significant modification of sponges morphological structure as well as reduction of the thermal stability and mechanical behaviour